-module(gleam@iterator_test).
-compile(no_auto_import).

-export([to_from_list_test/0, step_test/0, take_test/0, fold_test/0, map_test/0, flat_map_test/0, append_test/0, flatten_test/0, filter_test/0, repeat_test/0, cycle_test/0, unfold_test/0, range_test/0, drop_test/0, find_test/0, index_test/0, iterate_test/0, take_while_test/0, drop_while_test/0, scan_test/0, zip_test/0, chunk_test/0, sized_chunk_test/0, intersperse_test/0, any_test/0, all_test/0, group_test/0, reduce_test/0, last_test/0, empty_test/0, once_test/0, single_test/0, interleave_test/0]).
-export_type([cat/0]).

-type cat() :: {cat, integer()}.

-spec to_from_list_test() -> gleam@should:expectation().
to_from_list_test() ->
    Test = fun(Subject) ->
        gleam@should:equal(
            gleam@iterator:to_list(gleam@iterator:from_list(Subject)),
            Subject
        )
    end,
    Test([]),
    Test([1]),
    Test([1, 2]),
    Test([1, 2, 4, 8]).

-spec step_test() -> gleam@should:expectation().
step_test() ->
    Test = fun(Subject) ->
        Step = gleam@iterator:step(gleam@iterator:from_list(Subject)),
        case Subject of
            [] ->
                gleam@should:equal(Step, done);

            [H | T] ->
                gleam@should:equal(Step, {next, H, gleam@iterator:from_list(T)})
        end
    end,
    Test([]),
    Test([1]),
    Test([1, 2]),
    Test([1, 2, 3]).

-spec take_test() -> gleam@should:expectation().
take_test() ->
    Test = fun(N, Subject) ->
        gleam@should:equal(
            gleam@iterator:to_list(
                gleam@iterator:take(gleam@iterator:from_list(Subject), N)
            ),
            gleam@list:take(Subject, N)
        )
    end,
    Test(0, []),
    Test(1, []),
    Test(-1, []),
    Test(0, [0]),
    Test(1, [0]),
    Test(-1, [0]),
    Test(0, [0, 1, 2, 3, 4]),
    Test(1, [0, 1, 2, 3, 4]),
    Test(2, [0, 1, 2, 3, 4]),
    Test(22, [0, 1, 2, 3, 4]).

-spec fold_test() -> gleam@should:expectation().
fold_test() ->
    Test = fun(Subject, Acc, F) ->
        gleam@should:equal(
            gleam@iterator:fold(gleam@iterator:from_list(Subject), Acc, F),
            gleam@list:fold(Subject, Acc, F)
        )
    end,
    F@1 = fun(E, Acc@1) -> [E | Acc@1] end,
    Test([], [], F@1),
    Test([1], [], F@1),
    Test([1, 2, 3], [], F@1),
    Test([1, 2, 3, 4, 5, 6, 7, 8], [], F@1).

-spec map_test() -> gleam@should:expectation().
map_test() ->
    Test = fun(Subject, F) ->
        gleam@should:equal(
            gleam@iterator:to_list(
                gleam@iterator:map(gleam@iterator:from_list(Subject), F)
            ),
            gleam@list:map(Subject, F)
        )
    end,
    F@1 = fun(E) -> E * 2 end,
    Test([], F@1),
    Test([1], F@1),
    Test([1, 2, 3], F@1),
    Test([1, 2, 3, 4, 5, 6, 7, 8], F@1).

-spec flat_map_test() -> gleam@should:expectation().
flat_map_test() ->
    Test = fun(Subject, F) ->
        gleam@should:equal(
            gleam@iterator:to_list(
                gleam@iterator:flat_map(gleam@iterator:from_list(Subject), F)
            ),
            gleam@list:flatten(
                gleam@list:map(
                    gleam@list:map(Subject, F),
                    fun gleam@iterator:to_list/1
                )
            )
        )
    end,
    F@1 = fun(I) -> gleam@iterator:range(I, I + 2) end,
    Test([], F@1),
    Test([1], F@1),
    Test([1, 2], F@1).

-spec append_test() -> gleam@should:expectation().
append_test() ->
    Test = fun(Left, Right) ->
        gleam@should:equal(
            gleam@iterator:to_list(
                gleam@iterator:append(
                    gleam@iterator:from_list(Left),
                    gleam@iterator:from_list(Right)
                )
            ),
            gleam@list:flatten([Left, Right])
        )
    end,
    Test([], []),
    Test([1], [2]),
    Test([1, 2], [3, 4]).

-spec flatten_test() -> gleam@should:expectation().
flatten_test() ->
    Test = fun(Lists) ->
        gleam@should:equal(
            gleam@iterator:to_list(
                gleam@iterator:flatten(
                    gleam@iterator:from_list(
                        gleam@list:map(Lists, fun gleam@iterator:from_list/1)
                    )
                )
            ),
            gleam@list:flatten(Lists)
        )
    end,
    Test([[], []]),
    Test([[1], [2]]),
    Test([[1, 2], [3, 4]]).

-spec filter_test() -> gleam@should:expectation().
filter_test() ->
    Test = fun(Subject, F) ->
        gleam@should:equal(
            gleam@iterator:to_list(
                gleam@iterator:filter(gleam@iterator:from_list(Subject), F)
            ),
            gleam@list:filter(Subject, F)
        )
    end,
    Even = fun(X) -> (X rem 2) =:= 0 end,
    Test([], Even),
    Test([1], Even),
    Test([1, 2], Even),
    Test([1, 2, 3], Even),
    Test([1, 2, 3, 4], Even),
    Test([1, 2, 3, 4, 5], Even),
    Test([1, 2, 3, 4, 5, 6], Even).

-spec repeat_test() -> gleam@should:expectation().
repeat_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(gleam@iterator:take(gleam@iterator:repeat(1), 5)),
        [1, 1, 1, 1, 1]
    ).

-spec cycle_test() -> gleam@should:expectation().
cycle_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:take(
                gleam@iterator:cycle(gleam@iterator:from_list([1, 2, 3])),
                9
            )
        ),
        [1, 2, 3, 1, 2, 3, 1, 2, 3]
    ).

-spec unfold_test() -> gleam@should:expectation().
unfold_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:take(
                gleam@iterator:unfold(2, fun(Acc) -> {next, Acc, Acc * 2} end),
                5
            )
        ),
        [2, 4, 8, 16, 32]
    ),
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:take(gleam@iterator:unfold(2, fun(_) -> done end), 5)
        ),
        []
    ),
    gleam@should:equal(
        gleam@iterator:to_list(gleam@iterator:unfold(5, fun(N) -> case N of
                        0 ->
                            done;

                        N@1 ->
                            {next, N@1, N@1 - 1}
                    end end)),
        [5, 4, 3, 2, 1]
    ).

-spec range_test() -> gleam@should:expectation().
range_test() ->
    Test = fun(A, B, Expected) ->
        gleam@should:equal(
            gleam@iterator:to_list(gleam@iterator:range(A, B)),
            Expected
        )
    end,
    Test(0, 0, []),
    Test(1, 1, []),
    Test(-1, -1, []),
    Test(0, 1, [0]),
    Test(0, 5, [0, 1, 2, 3, 4]),
    Test(1, -5, [1, 0, -1, -2, -3, -4]).

-spec drop_test() -> gleam@should:expectation().
drop_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:drop(gleam@iterator:range(0, 10), 5)
        ),
        [5, 6, 7, 8, 9]
    ).

-spec find_test() -> gleam@should:expectation().
find_test() ->
    gleam@should:equal(
        gleam@iterator:find(gleam@iterator:range(0, 10), fun(E) -> E =:= 5 end),
        {ok, 5}
    ),
    gleam@should:equal(
        gleam@iterator:find(
            gleam@iterator:range(0, 10),
            fun(E@1) -> E@1 > 10 end
        ),
        {error, nil}
    ),
    gleam@should:equal(
        gleam@iterator:find(gleam@iterator:empty(), fun(_) -> true end),
        {error, nil}
    ),
    gleam@should:equal(
        gleam@iterator:find(
            gleam@iterator:unfold(
                {cat, 1},
                fun(Cat) -> {next, Cat, {cat, erlang:element(2, Cat) + 1}} end
            ),
            fun(Cat@1) -> erlang:element(2, Cat@1) =:= 10 end
        ),
        {ok, {cat, 10}}
    ).

-spec index_test() -> gleam@should:expectation().
index_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:index(
                gleam@iterator:from_list(
                    [<<"a"/utf8>>, <<"b"/utf8>>, <<"c"/utf8>>]
                )
            )
        ),
        [{0, <<"a"/utf8>>}, {1, <<"b"/utf8>>}, {2, <<"c"/utf8>>}]
    ).

-spec iterate_test() -> gleam@should:expectation().
iterate_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:take(
                gleam@iterator:iterate(1, fun(X) -> X * 3 end),
                5
            )
        ),
        [1, 3, 9, 27, 81]
    ).

-spec take_while_test() -> gleam@should:expectation().
take_while_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:take_while(
                gleam@iterator:from_list([1, 2, 3, 2, 4]),
                fun(X) -> X < 3 end
            )
        ),
        [1, 2]
    ).

-spec drop_while_test() -> gleam@should:expectation().
drop_while_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:drop_while(
                gleam@iterator:from_list([1, 2, 3, 4, 2, 5]),
                fun(X) -> X < 4 end
            )
        ),
        [4, 2, 5]
    ).

-spec scan_test() -> gleam@should:expectation().
scan_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:scan(
                gleam@iterator:from_list([1, 2, 3, 4, 5]),
                0,
                fun(El, Acc) -> Acc + El end
            )
        ),
        [1, 3, 6, 10, 15]
    ).

-spec zip_test() -> gleam@should:expectation().
zip_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:zip(
                gleam@iterator:from_list(
                    [<<"a"/utf8>>, <<"b"/utf8>>, <<"c"/utf8>>]
                ),
                gleam@iterator:range(20, 30)
            )
        ),
        [{<<"a"/utf8>>, 20}, {<<"b"/utf8>>, 21}, {<<"c"/utf8>>, 22}]
    ).

-spec chunk_test() -> gleam@should:expectation().
chunk_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:chunk(
                gleam@iterator:from_list([1, 2, 2, 3, 4, 4, 6, 7, 7]),
                fun(N) -> N rem 2 end
            )
        ),
        [[1], [2, 2], [3], [4, 4, 6], [7, 7]]
    ).

-spec sized_chunk_test() -> gleam@should:expectation().
sized_chunk_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:sized_chunk(
                gleam@iterator:from_list([1, 2, 3, 4, 5, 6]),
                2
            )
        ),
        [[1, 2], [3, 4], [5, 6]]
    ),
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:sized_chunk(
                gleam@iterator:from_list([1, 2, 3, 4, 5, 6, 7, 8]),
                3
            )
        ),
        [[1, 2, 3], [4, 5, 6], [7, 8]]
    ).

-spec intersperse_test() -> gleam@should:expectation().
intersperse_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:intersperse(gleam@iterator:empty(), 0)
        ),
        []
    ),
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:intersperse(gleam@iterator:from_list([1]), 0)
        ),
        [1]
    ),
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:intersperse(
                gleam@iterator:from_list([1, 2, 3, 4, 5]),
                0
            )
        ),
        [1, 0, 2, 0, 3, 0, 4, 0, 5]
    ).

-spec any_test() -> gleam@should:expectation().
any_test() ->
    gleam@should:be_false(
        gleam@iterator:any(
            gleam@iterator:empty(),
            fun(N) -> (N rem 2) =:= 0 end
        )
    ),
    gleam@should:be_true(
        gleam@iterator:any(
            gleam@iterator:from_list([1, 2, 5, 7, 9]),
            fun(N@1) -> (N@1 rem 2) =:= 0 end
        )
    ),
    gleam@should:be_false(
        gleam@iterator:any(
            gleam@iterator:from_list([1, 3, 5, 7, 9]),
            fun(N@2) -> (N@2 rem 2) =:= 0 end
        )
    ).

-spec all_test() -> gleam@should:expectation().
all_test() ->
    gleam@should:be_true(
        gleam@iterator:all(
            gleam@iterator:empty(),
            fun(N) -> (N rem 2) =:= 0 end
        )
    ),
    gleam@should:be_true(
        gleam@iterator:all(
            gleam@iterator:from_list([2, 4, 6, 8]),
            fun(N@1) -> (N@1 rem 2) =:= 0 end
        )
    ),
    gleam@should:be_false(
        gleam@iterator:all(
            gleam@iterator:from_list([2, 4, 5, 8]),
            fun(N@2) -> (N@2 rem 2) =:= 0 end
        )
    ).

-spec group_test() -> gleam@should:expectation().
group_test() ->
    gleam@should:equal(
        gleam@iterator:group(
            gleam@iterator:from_list([1, 2, 3, 4, 5, 6]),
            fun(N) -> N rem 3 end
        ),
        gleam@map:from_list([{0, [3, 6]}, {1, [1, 4]}, {2, [2, 5]}])
    ).

-spec reduce_test() -> gleam@should:expectation().
reduce_test() ->
    gleam@should:equal(
        gleam@iterator:reduce(gleam@iterator:empty(), fun(X, Y) -> X + Y end),
        {error, nil}
    ),
    gleam@should:equal(
        gleam@iterator:reduce(
            gleam@iterator:from_list([1, 2, 3, 4, 5]),
            fun(X@1, Y@1) -> X@1 + Y@1 end
        ),
        {ok, 15}
    ).

-spec last_test() -> gleam@should:expectation().
last_test() ->
    gleam@should:equal(
        gleam@iterator:last(gleam@iterator:empty()),
        {error, nil}
    ),
    gleam@should:equal(
        gleam@iterator:last(gleam@iterator:range(1, 10)),
        {ok, 9}
    ).

-spec empty_test() -> gleam@should:expectation().
empty_test() ->
    gleam@should:equal(gleam@iterator:to_list(gleam@iterator:empty()), []).

-spec once_test() -> gleam@should:expectation().
once_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(gleam@iterator:once(fun() -> 1 end)),
        [1]
    ).

-spec single_test() -> gleam@should:expectation().
single_test() ->
    gleam@should:equal(gleam@iterator:to_list(gleam@iterator:single(1)), [1]).

-spec interleave_test() -> gleam@should:expectation().
interleave_test() ->
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:interleave(
                gleam@iterator:from_list([1, 2, 3, 4]),
                gleam@iterator:from_list([11, 12, 13, 14])
            )
        ),
        [1, 11, 2, 12, 3, 13, 4, 14]
    ),
    gleam@should:equal(
        gleam@iterator:to_list(
            gleam@iterator:interleave(
                gleam@iterator:from_list([1, 2, 3, 4]),
                gleam@iterator:from_list([100])
            )
        ),
        [1, 100, 2, 3, 4]
    ).